1 =================================
2 LLVM Testing Infrastructure Guide
3 =================================
5 Written by John T. Criswell, Daniel Dunbar, Reid Spencer, and Tanya
14 TestSuiteMakefileGuide
19 This document is the reference manual for the LLVM testing
20 infrastructure. It documents the structure of the LLVM testing
21 infrastructure, the tools needed to use it, and how to add and run
27 In order to use the LLVM testing infrastructure, you will need all of
28 the software required to build LLVM, as well as
29 `Python <http://python.org>`_ 2.4 or later.
31 LLVM testing infrastructure organization
32 ========================================
34 The LLVM testing infrastructure contains two major categories of tests:
35 regression tests and whole programs. The regression tests are contained
36 inside the LLVM repository itself under ``llvm/test`` and are expected
37 to always pass -- they should be run before every commit.
39 The whole programs tests are referred to as the "LLVM test suite" (or
40 "test-suite") and are in the ``test-suite`` module in subversion. For
41 historical reasons, these tests are also referred to as the "nightly
42 tests" in places, which is less ambiguous than "test-suite" and remains
43 in use although we run them much more often than nightly.
48 The regression tests are small pieces of code that test a specific
49 feature of LLVM or trigger a specific bug in LLVM. The language they are
50 written in depends on the part of LLVM being tested. These tests are driven by
51 the :doc:`Lit <CommandGuide/lit>` testing tool (which is part of LLVM), and
52 are located in the ``llvm/test`` directory.
54 Typically when a bug is found in LLVM, a regression test containing just
55 enough code to reproduce the problem should be written and placed
56 somewhere underneath this directory. For example, it can be a small
57 piece of LLVM IR distilled from an actual application or benchmark.
62 The test suite contains whole programs, which are pieces of code which
63 can be compiled and linked into a stand-alone program that can be
64 executed. These programs are generally written in high level languages
67 These programs are compiled using a user specified compiler and set of
68 flags, and then executed to capture the program output and timing
69 information. The output of these programs is compared to a reference
70 output to ensure that the program is being compiled correctly.
72 In addition to compiling and executing programs, whole program tests
73 serve as a way of benchmarking LLVM performance, both in terms of the
74 efficiency of the programs generated as well as the speed with which
75 LLVM compiles, optimizes, and generates code.
77 The test-suite is located in the ``test-suite`` Subversion module.
79 Debugging Information tests
80 ---------------------------
82 The test suite contains tests to check quality of debugging information.
83 The test are written in C based languages or in LLVM assembly language.
85 These tests are compiled and run under a debugger. The debugger output
86 is checked to validate of debugging information. See README.txt in the
87 test suite for more information . This test suite is located in the
88 ``debuginfo-tests`` Subversion module.
93 The tests are located in two separate Subversion modules. The
94 regressions tests are in the main "llvm" module under the directory
95 ``llvm/test`` (so you get these tests for free with the main LLVM tree).
96 Use ``make check-all`` to run the regression tests after building LLVM.
98 The more comprehensive test suite that includes whole programs in C and C++
99 is in the ``test-suite`` module. See :ref:`test-suite Quickstart
100 <test-suite-quickstart>` for more information on running these tests.
105 To run all of the LLVM regression tests, use the master Makefile in the
106 ``llvm/test`` directory. LLVM Makefiles require GNU Make (read the :doc:`LLVM
107 Makefile Guide <MakefileGuide>` for more details):
119 If you have `Clang <http://clang.llvm.org/>`_ checked out and built, you
120 can run the LLVM and Clang tests simultaneously using:
126 To run the tests with Valgrind (Memcheck by default), just append
127 ``VG=1`` to the commands above, e.g.:
133 To run individual tests or subsets of tests, you can use the ``llvm-lit``
134 script which is built as part of LLVM. For example, to run the
135 ``Integer/BitPacked.ll`` test by itself you can run:
139 % llvm-lit ~/llvm/test/Integer/BitPacked.ll
141 or to run all of the ARM CodeGen tests:
145 % llvm-lit ~/llvm/test/CodeGen/ARM
147 For more information on using the :program:`lit` tool, see ``llvm-lit --help``
148 or the :doc:`lit man page <CommandGuide/lit>`.
150 Debugging Information tests
151 ---------------------------
153 To run debugging information tests simply checkout the tests inside
154 clang/test directory.
159 % svn co http://llvm.org/svn/llvm-project/debuginfo-tests/trunk debuginfo-tests
161 These tests are already set up to run as part of clang regression tests.
163 Regression test structure
164 =========================
166 The LLVM regression tests are driven by :program:`lit` and are located in the
167 ``llvm/test`` directory.
169 This directory contains a large array of small tests that exercise
170 various features of LLVM and to ensure that regressions do not occur.
171 The directory is broken into several sub-directories, each focused on a
172 particular area of LLVM.
174 Writing new regression tests
175 ----------------------------
177 The regression test structure is very simple, but does require some
178 information to be set. This information is gathered via ``configure``
179 and is written to a file, ``lit.site.cfg`` in ``llvm/test``. The
180 ``llvm/test`` Makefile does this work for you.
182 In order for the regression tests to work, each directory of tests must
183 have a ``lit.local.cfg`` file. Lit looks for this file to determine how
184 to run the tests. This file is just Python code and thus is very
185 flexible, but we've standardized it for the LLVM regression tests. If
186 you're adding a directory of tests, just copy ``lit.local.cfg`` from
187 another directory to get running. The standard ``lit.local.cfg`` simply
188 specifies which files to look in for tests. Any directory that contains
189 only directories does not need the ``lit.local.cfg`` file. Read the :doc:`Lit
190 documentation <CommandGuide/lit>` for more information.
192 The ``llvm-runtests`` function looks at each file that is passed to it
193 and gathers any lines together that match "RUN:". These are the "RUN"
194 lines that specify how the test is to be run. So, each test script must
195 contain RUN lines if it is to do anything. If there are no RUN lines,
196 the ``llvm-runtests`` function will issue an error and the test will
199 RUN lines are specified in the comments of the test program using the
200 keyword ``RUN`` followed by a colon, and lastly the command (pipeline)
201 to execute. Together, these lines form the "script" that
202 ``llvm-runtests`` executes to run the test case. The syntax of the RUN
203 lines is similar to a shell's syntax for pipelines including I/O
204 redirection and variable substitution. However, even though these lines
205 may *look* like a shell script, they are not. RUN lines are interpreted
206 directly by the Tcl ``exec`` command. They are never executed by a
207 shell. Consequently the syntax differs from normal shell script syntax
208 in a few ways. You can specify as many RUN lines as needed.
210 lit performs substitution on each RUN line to replace LLVM tool names
211 with the full paths to the executable built for each tool (in
212 $(LLVM\_OBJ\_ROOT)/$(BuildMode)/bin). This ensures that lit does not
213 invoke any stray LLVM tools in the user's path during testing.
215 Each RUN line is executed on its own, distinct from other lines unless
216 its last character is ``\``. This continuation character causes the RUN
217 line to be concatenated with the next one. In this way you can build up
218 long pipelines of commands without making huge line lengths. The lines
219 ending in ``\`` are concatenated until a RUN line that doesn't end in
220 ``\`` is found. This concatenated set of RUN lines then constitutes one
221 execution. Tcl will substitute variables and arrange for the pipeline to
222 be executed. If any process in the pipeline fails, the entire line (and
223 test case) fails too.
225 Below is an example of legal RUN lines in a ``.ll`` file:
229 ; RUN: llvm-as < %s | llvm-dis > %t1
230 ; RUN: llvm-dis < %s.bc-13 > %t2
233 As with a Unix shell, the RUN: lines permit pipelines and I/O
234 redirection to be used. However, the usage is slightly different than
235 for Bash. To check what's legal, see the documentation for the `Tcl
236 exec <http://www.tcl.tk/man/tcl8.5/TclCmd/exec.htm#M2>`_ command and the
237 `tutorial <http://www.tcl.tk/man/tcl8.5/tutorial/Tcl26.html>`_. The
238 major differences are:
240 - You can't do ``2>&1``. That will cause Tcl to write to a file named
241 ``&1``. Usually this is done to get stderr to go through a pipe. You
242 can do that in tcl with ``|&`` so replace this idiom:
243 ``... 2>&1 | grep`` with ``... |& grep``
244 - You can only redirect to a file, not to another descriptor and not
245 from a here document.
246 - tcl supports redirecting to open files with the @ syntax but you
247 shouldn't use that here.
249 There are some quoting rules that you must pay attention to when writing
250 your RUN lines. In general nothing needs to be quoted. Tcl won't strip
251 off any quote characters so they will get passed to the invoked program.
256 ... | grep 'find this string'
258 This will fail because the ' characters are passed to grep. This would
259 instruction grep to look for ``'find`` in the files ``this`` and
260 ``string'``. To avoid this use curly braces to tell Tcl that it should
261 treat everything enclosed as one value. So our example would become:
265 ... | grep {find this string}
267 Additionally, the characters ``[`` and ``]`` are treated specially by
268 Tcl. They tell Tcl to interpret the content as a command to execute.
269 Since these characters are often used in regular expressions this can
270 have disastrous results and cause the entire test run in a directory to
271 fail. For example, a common idiom is to look for some basicblock number:
277 This, however, will cause Tcl to fail because its going to try to
278 execute a program named "2-8". Instead, what you want is this:
282 ... | grep {bb\[2-8\]}
284 Finally, if you need to pass the ``\`` character down to a program, then
285 it must be doubled. This is another Tcl special character. So, suppose
292 This will fail to match what you want (a pointer to i32). First, the
293 ``'`` do not get stripped off. Second, the ``\`` gets stripped off by
294 Tcl so what grep sees is: ``'i32*'``. That's not likely to match
295 anything. To resolve this you must use ``\\`` and the ``{}``, like this:
301 If your system includes GNU ``grep``, make sure that ``GREP_OPTIONS`` is
302 not set in your environment. Otherwise, you may get invalid results
303 (both false positives and false negatives).
305 The FileCheck utility
306 ---------------------
308 A powerful feature of the RUN: lines is that it allows any arbitrary
309 commands to be executed as part of the test harness. While standard
310 (portable) unix tools like 'grep' work fine on run lines, as you see
311 above, there are a lot of caveats due to interaction with Tcl syntax,
312 and we want to make sure the run lines are portable to a wide range of
313 systems. Another major problem is that grep is not very good at checking
314 to verify that the output of a tools contains a series of different
315 output in a specific order. The FileCheck tool was designed to help with
318 FileCheck is designed to read a file to check from standard input, and the set
319 of things to verify from a file specified as a command line argument.
320 FileCheck is described in :doc:`the FileCheck man page
321 <CommandGuide/FileCheck>`.
323 Variables and substitutions
324 ---------------------------
326 With a RUN line there are a number of substitutions that are permitted.
327 In general, any Tcl variable that is available in the ``substitute``
328 function (in ``test/lib/llvm.exp``) can be substituted into a RUN line.
329 To make a substitution just write the variable's name preceded by a $.
330 Additionally, for compatibility reasons with previous versions of the
331 test library, certain names can be accessed with an alternate syntax: a
332 % prefix. These alternates are deprecated and may go away in a future
335 Here are the available variable names. The alternate syntax is listed in
339 The full path to the test case's source. This is suitable for passing on
340 the command line as the input to an llvm tool.
342 ``%(line)``, ``%(line+<number>)``, ``%(line-<number>)``
343 The number of the line where this variable is used, with an optional
344 integer offset. This can be used in tests with multiple RUN: lines,
345 which reference test file's line numbers.
348 The source directory from where the "``make check``" was run.
351 The object directory that corresponds to the ``$srcdir``.
354 A partial path from the ``test`` directory that contains the
355 sub-directory that contains the test source being executed.
358 The root directory of the LLVM src tree.
361 The root directory of the LLVM object tree. This could be the same as
365 The path to the directory that contains the test case source. This is
366 for locating any supporting files that are not generated by the test,
367 but used by the test.
370 The path to a temporary file name that could be used for this test case.
371 The file name won't conflict with other test cases. You can append to it
372 if you need multiple temporaries. This is useful as the destination of
373 some redirected output.
375 ``target_triplet`` (``%target_triplet``)
376 The target triplet that corresponds to the current host machine (the one
377 running the test cases). This should probably be called "host".
380 This full link command used to link LLVM executables. This has all the
381 configured -I, -L and -l options.
383 ``shlibext`` (``%shlibext``)
384 The suffix for the host platforms share library (dll) files. This
385 includes the period as the first character.
387 To add more variables, two things need to be changed. First, add a line
388 in the ``test/Makefile`` that creates the ``site.exp`` file. This will
389 "set" the variable as a global in the site.exp file. Second, in the
390 ``test/lib/llvm.exp`` file, in the substitute proc, add the variable
391 name to the list of "global" declarations at the beginning of the proc.
392 That's it, the variable can then be used in test scripts.
397 To make RUN line writing easier, there are several shell scripts located
398 in the ``llvm/test/Scripts`` directory. This directory is in the PATH
399 when running tests, so you can just call these scripts using their name.
403 This script runs its arguments and then always returns 0. This is useful
404 in cases where the test needs to cause a tool to generate an error (e.g.
405 to check the error output). However, any program in a pipeline that
406 returns a non-zero result will cause the test to fail. This script
407 overcomes that issue and nicely documents that the test case is
408 purposefully ignoring the result code of the tool
410 This script runs its arguments and then inverts the result code from it.
411 Zero result codes become 1. Non-zero result codes become 0. This is
412 useful to invert the result of a grep. For example "not grep X" means
413 succeed only if you don't find X in the input.
415 Sometimes it is necessary to mark a test case as "expected fail" or
416 XFAIL. You can easily mark a test as XFAIL just by including ``XFAIL:``
417 on a line near the top of the file. This signals that the test case
418 should succeed if the test fails. Such test cases are counted separately
419 by the testing tool. To specify an expected fail, use the XFAIL keyword
420 in the comments of the test program followed by a colon and one or more
421 failure patterns. Each failure pattern can be either ``*`` (to specify
422 fail everywhere), or a part of a target triple (indicating the test
423 should fail on that platform), or the name of a configurable feature
424 (for example, ``loadable_module``). If there is a match, the test is
425 expected to fail. If not, the test is expected to succeed. To XFAIL
426 everywhere just specify ``XFAIL: *``. Here is an example of an ``XFAIL``
433 To make the output more useful, the ``llvm_runtest`` function wil scan
434 the lines of the test case for ones that contain a pattern that matches
435 ``PR[0-9]+``. This is the syntax for specifying a PR (Problem Report) number
436 that is related to the test case. The number after "PR" specifies the
437 LLVM bugzilla number. When a PR number is specified, it will be used in
438 the pass/fail reporting. This is useful to quickly get some context when
441 Finally, any line that contains "END." will cause the special
442 interpretation of lines to terminate. This is generally done right after
443 the last RUN: line. This has two side effects:
445 (a) it prevents special interpretation of lines that are part of the test
446 program, not the instructions to the test case, and
448 (b) it speeds things up for really big test cases by avoiding
449 interpretation of the remainder of the file.
451 ``test-suite`` Overview
452 =======================
454 The ``test-suite`` module contains a number of programs that can be
455 compiled and executed. The ``test-suite`` includes reference outputs for
456 all of the programs, so that the output of the executed program can be
457 checked for correctness.
459 ``test-suite`` tests are divided into three types of tests: MultiSource,
460 SingleSource, and External.
462 - ``test-suite/SingleSource``
464 The SingleSource directory contains test programs that are only a
465 single source file in size. These are usually small benchmark
466 programs or small programs that calculate a particular value. Several
467 such programs are grouped together in each directory.
469 - ``test-suite/MultiSource``
471 The MultiSource directory contains subdirectories which contain
472 entire programs with multiple source files. Large benchmarks and
473 whole applications go here.
475 - ``test-suite/External``
477 The External directory contains Makefiles for building code that is
478 external to (i.e., not distributed with) LLVM. The most prominent
479 members of this directory are the SPEC 95 and SPEC 2000 benchmark
480 suites. The ``External`` directory does not contain these actual
481 tests, but only the Makefiles that know how to properly compile these
482 programs from somewhere else. When using ``LNT``, use the
483 ``--test-externals`` option to include these tests in the results.
485 .. _test-suite-quickstart:
487 ``test-suite`` Quickstart
488 -------------------------
490 The modern way of running the ``test-suite`` is focused on testing and
491 benchmarking complete compilers using the
492 `LNT <http://llvm.org/docs/lnt>`_ testing infrastructure.
494 For more information on using LNT to execute the ``test-suite``, please
495 see the `LNT Quickstart <http://llvm.org/docs/lnt/quickstart.html>`_
498 ``test-suite`` Makefiles
499 ------------------------
501 Historically, the ``test-suite`` was executed using a complicated setup
502 of Makefiles. The LNT based approach above is recommended for most
503 users, but there are some testing scenarios which are not supported by
504 the LNT approach. In addition, LNT currently uses the Makefile setup
505 under the covers and so developers who are interested in how LNT works
506 under the hood may want to understand the Makefile based setup.
508 For more information on the ``test-suite`` Makefile setup, please see
509 the :doc:`Test Suite Makefile Guide <TestSuiteMakefileGuide>`.